function adatta_sfondo() {
  with (document) {
// controllo dimensioni minime dello schermo //
		if (getElementById('schermo').clientWidth < 940 || getElementById('schermo').clientHeight < 600)
			document.getElementById('avviso').style.display = "block";
		rapporto_foto = larghezza_foto/altezza_foto;
		rapporto_video = getElementById('schermo').clientWidth/getElementById('schermo').clientHeight;
		if (rapporto_video < rapporto_foto) {
			getElementById('foto_sfondo').style.height = getElementById('schermo').clientHeight+"px";
			getElementById('foto_sfondo').style.left = 0-(parseFloat(getElementById('foto_sfondo').style.height)*rapporto_foto-getElementById('schermo').clientWidth)/2+"px";
		} else {
			getElementById('foto_sfondo').style.width = getElementById('schermo').clientWidth+"px";
			getElementById('foto_sfondo').style.top = 0-(parseFloat(getElementById('foto_sfondo').style.width)*(1/rapporto_foto)-getElementById('schermo').clientHeight)/2+"px";
		}
		getElementById('menu').style.top = getElementById('barra_logo').offsetTop-246+"px";
		getElementById('box_news').style.top = getElementById('barra_logo').offsetTop-getElementById('box_news').clientHeight+"px";
		getElementById('box_news').style.left = getElementById('menu').offsetLeft-getElementById('box_news').clientWidth-9+"px";
		getElementById('ombra_credits').style.top = getElementById('schermo').clientHeight-getElementById('ombra_credits').clientHeight+"px";
		getElementById('ombra_credits').style.left = getElementById('schermo').clientWidth-getElementById('ombra_credits').clientWidth+"px";
		getElementById('dati_credits').style.top = getElementById('ombra_credits').offsetTop-getElementById('dati_credits').clientHeight+68+"px";
		getElementById('dati_credits').style.left = getElementById('ombra_credits').offsetLeft+187+"px";
		getElementById('lingue').style.top = getElementById('barra_logo').offsetTop+25+"px";
		getElementById('lingue').style.left = getElementById('menu').offsetLeft+"px";
		getElementById('fb_like').style.top = getElementById('barra_logo').offsetTop+22+"px";
		getElementById('fb_like').style.left = getElementById('menu').offsetLeft+getElementById('lingue').clientWidth+35+"px";
		getElementById('schermo').style.visibility = "visible";
	}
}

function credits(n) {
  with (document.getElementById('dati_credits').style) {
	  if (n == 1)
	    visibility = "visible";
		else
		  visibility = "hidden";
	}
}